Authors:

Understanding the mechanics of tissues at the scale of one to hundreds of microns is aforefront challenge in biomechanics. At this scale, the filamentous network of the extracellularmatrix (ECM) cannot be treated as an elastic continuum; forces propagate through it alongcomplex paths encompassing only a small fraction of the fibers. To map tensions in suchnetworks under load, we propose to monitor the transverse thermal fluctuations of multiplefibers. To that end, we discuss our calculations of the fiber fluctuations with various boundaryconditions, including complex junctions with other fibers. We also discuss fluctuations of fibersnear to their buckling transition. Finally, we address a self-consistent model of a fluctuatingfiber in a network of similar fibers. These calculations should inform a new sort ofmicrorheological tension mapping of the ECM via confocal fiber tracking.